Optical interference filter technology has provided films and/or coatings that are radio frequency (RF) transparent and infrared (IR) reflective. Currently, thin film multi-layer dielectric stacks are used for IR reflection and RF transparency. However, practical available IR reflecting dielectric materials are specular in their visual appearance.
Dielectric spheres have been coated with metal for use in polymer coatings requiring electrically conductive properties. These spheres have not been used as IR reflective pigments for signature control, because their high RF reflectance makes them unsuitable for many applications, for example, applications requiring IR treatment over radar absorbing materials. Also, the bright coated spheres are highly reflective in the visual spectrum.
It would be desirable to have coating materials which, when applied as a coating to an object such as a military system, will be IR reflective, RF transparent, visually colored and nonspecular.
The object of the invention is to provide infrared reflective coatings and coating materials having the desired characteristics.